This invention relates to the design of free floating, self-leveling, instant mounting, side-shield wing attachments for general utility open faced grading plows. More particularly, while the present invention is represented by several illustrations as configured to a standard vehicle mounted open faced snow plow, it is envisioned that the invention is applicable to the to-grade plowing of any solid-like movable matrix such as earth, gravel, grain, etc. The purpose of the side-shield wing attachments for such a general utility open faced grading plow is to retain the material being moved within the full contact face of the plow and inhibit spillage of said material around the ends of the moving plow face as furrows. In short, the side-shield wing attachments render an open faced plow into a closed face scoop. It is acknowledged that single unit construction closed faced scoop plows are an ancient design of universal utilization in to-grade plowing. Likewise, various designs of side-shield wing attachments which can convert an open faced grading plow into the closed face scoop configuration are commercially available. However, the features which render this invention unique and non-obvious are the presence of side-shield wing attachments that are free-floating and self-leveling relative to the cutting edge of the plow. Thus, vertical movement of the wing attachment is facilitated by means of a key mechanism which is free floating in a keyway mounted to the back of the plow face. In this fashion, the wing attachment can lift and reset itself into proper alignment with the surface grade upon contact with a rigid obstruction present in the surface being plowed, such as a curb. Moreover, the free floating design allows the side-shield wing to drop below the level of the plow cutting edge when a negative grade is encountered. In the absence of such a free floating and self-leveling design, temporary side-shield wing attachments are prone to excessive mechanical stress and breakage upon contact with rigid obstructions on the grade, and moreover, do not adjust to a negative grade. The alternative is to utilize a single unit closed face scoop plow of very robust construction. However, the closed face scoop plow design with permanent side wings is limited in its utility to only straight-on directional plowing. Secondly, a robust closed face scoop design usually adds disadvantageous excessive weight to the plow assembly. The advantage of an open faced plow design is that the absence of the side-shield wing attachment, the plow face may be set at an angle and spillage from the trailing open end of the plow allows for furrow angle plowing of the movable matrix. This is a common and usual practice in the removal of snow from a large surface by repeated displacement of the furrow through consecutive passage of the plow at an angle to the previously laid furrow. The present design allows for the instant mounting or demounting of the attachments by simply detaching a tension chain from a chain hook adapter and lifting the side-shield wing from its keyway adapter. Thus, the best utility features of both an open faced and closed face scoop plow are immediately realized as the task demands.
Some of the patents relating to applicant's invention include U.S. Pat. No. 3,805,424 in which Renahan discloses a snow plow wing which raises or retracts by means of a single hydraulic cylinder.
Bertolino in U.S. Pat. No. 4,145,825 describes retractable plow wings pivotally mounted on a plow blade.
In U.S. Pat. No. 4,356,645 Hine et al. disclose a plow blade with wing blades adjustable with motors and hydraulics.
Melby in U.S. Pat. No. 4,614,048 describes a plow wing portion pivotally adjustable by hydraulic means.
In U.S. Pat. No. 4,741,116 Engle et al. disclose a plow wing assembly fastened in a fixed orientation to a plow blade.
Zellaha et al. in U.S. Pat. No. 4,962,600 describe a shear pin hinged plow wing assembly for a plow blade.
In U.S. Pat. No. 5,148,617 Feller et al. disclose pivotally mounted wing blades for a plow blade.
Niemela et al. in U.S. Pat. No. 5,285,588 describe a plow blade with blade wings pivotally mounted at each end which adjust by mechanical or hydraulic means.
None of these inventions disclose or suggest applicant's invention described in detail below.